In a Dutch oven or soup pot (5 qt.) with a tight fitting lid, cook the bacon over medium-low heat until browned and crisp, 8-10 minutes. Pour off all but 1 Tablespoon of fat, if needed.

Add onion and carrots; cook until softened, about 5 minutes. Stir in the garlic, and cook until fragrant, about 30 seconds. Stir in the tomato paste and cook for 1 minute.

Add the lentils, thyme, broth and 2 cups water. Bring to a boil; reduce to a simmer. Cover and cook until lentils are tender, 30-45 minutes. If the soup becomes too thick during cooking, add up to 1 cup more water.